The present invention relates to an electromagnetically controlled door or gate opener for pivotable gates, doors, covers or the like pertaining to and covering, closing etc., boxlike casings, housings or the like.
Known electromagnetic door and gate openers include a closing sheet or locking plate having a cam for driving a one arm lever. The end of this lever rests on a blade of a control lever which in turn carries an elongated electromagnetic armature. The armature is maintained in a position of rest through the force of a spring and in that position the closing sheet or locking plate is locked or blocked. The electromagnet itself, moreover, is comprised of a U-shaped yoke with two rather strong coils. These coils will be energized with alternating current of low voltage and cause the yoke to attract the spring loaded armature whereby certain amount of lifting work is exerted and provided so that the aforementioned blade releases the lever as well as the locking plate. Since the magnetic force is effective across a rather larger air gap for purposes of moving the armature one needs a rather large operating current.